Polymer materials are used in the automotive industry and elsewhere, particularly for components with high aesthetic requirements. Compositions of polymer materials typically include a base polymer and additives, such as fiber reinforcement, fillers, stabilizers, flame retardants, and colorants that modify the properties of the base polymer.
Cellulose fibers are of interest for incorporation into polymer materials. Cellulose fibers generally have low density, good physical properties, and low cost. However, cellulose fibers also have characteristics that limit their use. For example, cellulose fibers readily absorb moisture, which is detrimental in exterior applications, and can reduce strength of the polymer material. Cellulose fibers also have a bright white color. In colored polymer materials (non-white) for molded-in color applications, the white color of the cellulose fibers degrades the colored aesthetic appearance. Accordingly, use of cellulose fibers in colored polymer materials has been limited.